The invention relates to a sensor which includes a sensor section having a sensor element, and an electronics section having a insert containing electronics, wherein the sensor section is protected against environmental conditions.
Sensors form the basis of industrial measuring and control engineering. For this reason they are used in virtually all facilities in the large industry sector, e.g., in chemistry, in the food industry and in water processing plants. These sensors are used on site to measure and/or monitor process quantities such as pressure, temperature, fluid level, flow or other quantities to be measured. The sensors are placed at a measuring point and contain a sensor element which registers the desired process quantity and changes it into an electric value. The electric value is sent to an electronic device, which further processes and converts this information into an electric output signal, which makes possible a display and/or the regulation of the measurement result.
A sensor typically includes a sensor section having a sensor element, and an electronics section having electronics. The electronics section must have an opening through which the electronics can be positioned, and the electronics in the electronics section must be connectable to the sensor element in the sensor section.
Sensors are regularly exposed to changing environmental conditions, above all else fluctuations in temperature, creating a danger that moisture can penetrate the device, which can greatly impair the function of the sensor element and/or the electronics.
Moisture penetrates, for example, if warm air with high humidity penetrates the sensor section and/or the electronics section and cools down. Upon cooling, the moisture contained in the air condenses and the accumulated water can no longer escape, or only escape very slowly from inside of the sensor.
In addition, moisture can penetrate if there is a temperature gradient between the inside of the sensor and its surroundings and the temperature falls below the dew point inside of the sensor. In this case, condensation also builds up on the inside of the sensor. The water trapped inside can no longer escape, or only escapes very slowly from inside of the sensor.
One objective of the present invention is to provide a sensor in which the sensor element is permanently protected against moisture.
A sensor of the present invention includes
a sensor section which includes a sensor element,
an electronics section which includes a insert containing electronics,
a passageway between the sensor section and the electronics section, through which the electronics section is connected to the sensor section, and
a connection element which connects the electrical connection of the sensor element to the electronics, the connection element
being an integral component of the insert,
extending into the passageway, and
sealing the passageway.
In accordance with one preferred embodiment of the invention, the hollow sections inside of the insert and inside the connection element integrated with the insert are filled with a filling material.
In accordance with another preferred embodiment of the invention, there is a seal between the passageway and the connection element.
In accordance with another preferred embodiment of the invention, an air filter is fitted in an exterior wall of the electronics section.
In accordance with another preferred embodiment of the invention, the electronics section is sealed with a removable cover.
The sensor of the present invention offers the advantage that, despite the necessary passageway between the sensor section and the electronics section, the interior is divided into two separate sections. Therefore the volume of the hollow section, which can act as an air absorbing pump volume if the temperature changes, is practically restricted to the free volume remaining in the electronics section. Moisture can therefore only penetrate the electronics section from outside, if at all. The sensor section is sealed and there is practically no exchange of air between the sensor section and the electronics section.
Another advantage of the sensor of the present invention is that it is modular. The electronics and sensor element are separate components which can be used independent of one another and are only linked via the connection element. The sensor can therefore be manufactured at little expense and offers a high degree of flexibility. For example, there could be a kit of various electronics and different types of sensor elements, which can be combined in any number of ways.